RUI: An Improved Measurement of the Electron-Antineutrino Correlation in Free Neutron Decay

电弱标准模型描述了宇宙中存在的四种基本力中的两种。通过进行实验，以越来越高的灵敏度探测可以用该模型描述的现象，希望能够出现差异，从而对弱相互作用有更全面的理解。这种相互作用导致中子衰变或转变为质子、电子和反中微子。通过研究中子性质与其衰变产物之间的相关性，可以对电弱标准模型进行更精确的测试。其中一种关联，被称为小“a”，涉及电子和反中微子从衰变区域发射的方向。已知其他中子衰变相关性在1%以内，但小“a”仅为4%。aCORN，中子衰变的“a”相关性，合作正在建造一个仪器，希望通过一种绕过先前实验中固有问题的方法，提供1%（如果不是更好的话）的“a”测量。该仪器将在印第安纳大学的低能中子源（LENS）进行测试，然后转移到NIST（国家科学技术研究所），那里有一个足够强大的中子源来进行测量。该基金支持来自德堡大学核物理组的aCORN合作者的贡献，包括本科生研究人员。因此，除了增加对弱相互作用的了解外，这些努力还将为本科生研究人员提供一个机会，亲身体验研究是如何进行的，并获得一套将在他们的余生中很好地服务的一般批判性思维技能。

The electroweak standard model describes two of the four fundamental forces present in the universe. By conducting experiments that probe with increasing sensitivity phenomena that can be described with this model, it is hoped discrepancies will appear that will lead to a more complete understanding of the weak interaction. This interaction is responsible for the decay, or transformation, of the neutron into a proton, electron and antineutrino. By studying the correlations between the properties of the neutron and its decay products, more precise tests of the electroweak standard model can be performed. One of these correlations, know as little "a", involves the direction of emission of the electron and antineutrino from the decay region. Other neutron decay correlations are known to within 1%, but little "a" is only known to 4%. The aCORN, "a" CORrelation in Neutron decay, collaboration is in the process of building an apparatus that hopes to provide a 1%, if not better, measurement of "a" using a method that bypasses some of the problems inherent in previous experiments. The apparatus will be tested at the Low Energy Neutron Source (LENS) at Indiana University and then moved to NIST (National Institute of Science and Technology) where there is a neutron source strong enough to perform the measurement. This grant supports the contributions of the aCORN collaborators from the DePauw University Nuclear Physics group, including undergraduate researchers. As such, in addition to increasing what is known about the weak interaction, these efforts will also provide an opportunity for undergraduate researchers to experience firsthand how research is conducted, and to acquire a set of general critical thinking skills that will serve them well the rest of their lives.